Buby is an Aurora Girl who makes northern lights together with her kind. She is banished from Aurora no kuni (Aurora Land) because of her selfishness and horrible behaviour, and she is told to find a stone called Aurora no Shizuku that can grant three wishes. That way she will be forgiven. Ruby meets Anpanman and lies to him that she needs the stone to rescue her land. But when Baikinman is also interested in getting the three wishes, Ruby is torn between the choice of helping her new friends or being able to return to Aurora no kuni. Ruby is one of the Aurora Girls responsible for painting of the auroras in the sky. She is banished from her homeland due to her selfishness and is told that she shall be forgiven if she is able to find the Aurora Drop, a mysterious item able to grant three wishes to whomever holds it. While searching for the hidden object, she meets Anpanman and his friends. They embark on a voyage to assist Ruby, but Baikinman and his gang are set on reaching the artifact before they do.